1. Field of the Invention
The present invention relates to an image recording apparatus which employs a solid-state image sensor in combination with a color separation filter assembly.
2. Description of the Related Art
Special attention has recently been directed to an apparatus for converting a signal output from a solid-state image sensor into a digital signal, applying digital signal processing to the digital signal, and recording or reproducing the signal as an image. A typical example of such an apparatus is a full-solid-state camera arranged to convert video information into a digital value and record it on a semiconductor memory or the like. In the aforesaid apparatus, it is necessary to execute various kinds of signal processing, depending on the arrangement of a color separation filter assembly attached to the image sensor (hereinafter referred to as a xe2x80x9csensorxe2x80x9d). Accordingly, in an electronic camera, video information is converted into a standard signal form which does not depend on the arrangement of the color separation filters, for example, either a luminance signal and color-difference signals or R, G and B signals, and the thus-converted signals are recorded on a semiconductor memory or the like.
However, the aforesaid conventional arrangement has a problem in that information is recorded on the memory in an amount which is larger than the original amount. For example, in an arrangement in which the output of a sensor having general complementary color mosaic filters is fetched into a memory, the memory capacity required for the luminance signal is needed by an amount approximately corresponding to the number of pixels on the sensor since a sampling frequency cannot be reduced. In addition, since it is necessary to convert color-difference signals which are originally obtained in a line-sequential manner into simultaneous signals to be stored, a memory capacity needs to be several times as large as the original amount of information supplied from the sensor. Of course, it is possible to lower the sampling frequency of each of the color-difference signals. However, in order to lower such sampling frequency, a digital filter is needed. Furthermore, since the sampling frequency cannot be lowered below a certain limit, it is difficult to prevent the required memory capacity from increasing to a great extent above the original amount of information supplied from the sensor. The above problem is also experienced with a sensor having pure color stripe filters which will be described later. In order to store the original information on the memory without increasing the amount of information, it is necessary to directly record the information supplied from the sensor. However, since different kinds of color filters require different forms of signal processing, the problem that interchangeability is not assured remains to be solved.
It is, therefore, an object of the present invention to provide an image recording apparatus which is capable of solving the above-described prior art problem.
To this end, according to one embodiment of the present invention, there is provided an image recording apparatus which comprises a memory for directly storing a color signal supplied from a solid-state image sensor in a memory without applying color signal processing to that color signal, selecting means for selecting block data of arbitrary size from the memory, and a matrix calculation circuit for converting the selected block data into a predetermined color or luminance signal.
In a specific form of the aforesaid embodiment, a reproducing apparatus is provided with an nxc3x97m matrix signal processing means for converting a signal supplied from a sensor into R, G and B signals as well as a luminance signal. In recording mode, a recording apparatus is adapted to directly store the signal output form the sensor in its memory and to record on the memory the requisite information such as a conversion matrix constant, information on the lattice arrangement of the sensor, and the number of steps of horizontal and vertical movements. Accordingly, it is possible to produce a signal output having a common form with respect to an arbitrary arrangement of colors.
In accordance with the above-described embodiment, if the signal output from the sensor is substantially directly written to the memory, interchangeability is not impaired and outstanding memory saving can be achieved.
In accordance with another embodiment of the present invention, there is provided an electronic camera which is arranged to record on a detachable memory an image signal and information indicative of the characteristics of an image sensor.
In this embodiment, it is possible to record the output of the image sensor in substantially unprocessed form, whereby image information can be recorded with the amount of information per image reduced. In addition, since information on the property of the image sensor is stored, the stored image information can be readily converted into image information having interchangeability in a final step.
Further objects, features and advantages of the present invention will become apparent form the following detailed description of embodiments of the present invention with reference to the accompanying drawings.